DNA Technology
DNA Extraction Chemical treatments cause cells and nuclei to burst The DNA is inherently sticky, and can be pulled out of the mixture This is called “spooling” DNA
“Spooled” DNA
Cutting DNA Restriction enzymes cut DNA at specific sequences Useful to divide DNA into manageable fragments
Electrophoresis DNA can be separated based on size and charge The phosphate groups are negatively charged DNA is placed in a gel and electricity is run through
Electrophoresis Negative DNA moves toward the positive end Smaller fragments move farther and faster
Electrophoresis
Steps in DNA Sequencing Many copies of a single strand of DNA are placed in a test tube DNA polymerase is added A mixture of nucleotides is added some of which have dye molecules attached Each base (A,T,C,G) has a different color dye
Steps in DNA Sequencing By chance, some dyed nucleotides & some regular ones are added Dye molecules are large and stop the chain from growing
DNA Sequencing The result is DNA fragments of multiple sizes with colors that can be identified
DNA Sequencing After the gel separates the resulting fragments by size, we 'read' the sequence from bottom to top.
Copying DNA Polymerase Chain Reaction Also called PCR A method of making many copies of a piece of DNA
Steps in Copying DNA A DNA molecule is placed in a small test tube DNA polymerase that can work at high temps is added
Steps in Copying DNA The DNA is heated to separate the two strands Primers, short pieces of DNA complementary to the ends of the molecule to be copied, are added
Copying DNA The tube is cooled, and DNA polymerase adds new bases to the separated strands
Large amounts of DNA can be made from a small starting sample PCR Large amounts of DNA can be made from a small starting sample
Cloning Clone- a member of a group of genetically identical cells May be produced by asexual reproduction (mitosis)
Cloning organisms A body cell from one organism and an egg cell from another are fused The resulting cell divides like a normal embryo
Cloning “Dolly”